Field of the Invention
The invention relates to a Coriolis mass flowmeter having at least one measuring tube excitable to oscillations, at least one oscillation generator, at least two oscillation sensors for receiving opposingly influenced oscillation parts of the measuring tube oscillation, at least one evaluation unit and at least two holding devices for holding the oscillation sensors, wherein at least one part of an oscillation sensor is attached to each holding device.
Description of Related Art
Coriolis mass flowmeters are known in the prior art in a plurality of designs. Mass flowmeters that function using the Coriolis principle usually have at least one oscillation generator, with which the measuring tube is excited to oscillation—or possibly also several measuring tubes are excited to oscillation—and often have two oscillation sensors, with which the obtained oscillation or obtained oscillations of the measuring tube is/are recorded. The oscillation sensors are usually attached to the measuring tube on the inlet and outlet side. Without flow, the signals of the two oscillation sensors are essentially in phase. In the case of mass flow, there is differently-directed Coriolis force at the input and output side, which leads to a phase shift between deflections and thus between the two signals, wherein the phase shift is proportional to the mass flow within the measuring tube; this is what is meant when it is said that the oscillation sensors are designed for receiving opposingly influenced oscillation parts.
The oscillation generator and the oscillation sensors are mostly constructed so that they have a permanent magnet as well as a coil, in order to transmit oscillations to the measuring tube using electrical means or to record oscillations of the measuring tube.
From experience, the applicant has knowledge of Coriolis mass flowmeters with one measuring tube or also several measuring tubes, one oscillation generator and two oscillation sensors, in which the oscillation sensors are attached to a holding device on the input and output side and are connected to the tube by means of the holding device. The Coriolis mass flowmeters known from the prior art, however, have the disadvantage that, in the case of malfunction or defect of even only one of the oscillation sensors, the sensors can only be exchanged or serviced with difficulty or by interrupting running production, which, in production of high-grade end products, can lead to substantial economic and also technical disadvantages. Additionally, a particular demand is placed on the measuring accuracy in the production of high-grade components. This means more than being as accurate as possible, in that a constant high quality is maintained over a long period of time.